Switched capacitor amplifiers include an Op-Amp-based amplifier that uses an operational amplifier, and a comparator-based amplifier that uses a comparator. Comparator-based amplifiers are of low power consumption as they do not require an operational amplifier consuming a large power; however, they involve a drawback, namely, a large offset voltage due to a comparator delay. This is because, even after an input signal and a feedback signal match with each other, capacity is charged excessively as much as the delay time from the matching of the input signal and the feedback signal to the inverting of the comparator's output. It has been a demand for comparator-based amplifiers to reduce the offset voltage of a comparator.